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sodium_crypto_secretbox_open

(PHP 7 >= 7.2.0, PHP 8)

sodium_crypto_secretbox_open — Authenticated shared-key decryption

Beschreibung

sodium_crypto_secretbox_open(string $ciphertext, string $nonce, string $key): string|false

Decrypt an encrypted message with a symmetric (shared) key.

Parameter-Liste

ciphertext: Must be in the format provided by sodium_crypto_secretbox() (ciphertext and tag, concatenated).
nonce: A number that must be only used once, per message. 24 bytes long. This is a large enough bound to generate randomly (i.e. random_bytes()).
key: Encryption key (256-bit).

Rückgabewerte

The decrypted string on successBei einem Fehler wird false zurückgegeben..

Fehler/Exceptions

If nonce has a length of bytes different than SODIUM_CRYPTO_SECRETBOX_NONCEBYTES (24 bytes), a SodiumException will be thrown.
If key has a length of bytes different than SODIUM_CRYPTO_SECRETBOX_KEYBYTES (32 bytes), a SodiumException will be thrown.

Beispiele

Beispiel #1 sodium_crypto_secretbox_open() example

<?php
// The $key must be kept confidential
$key = random_bytes(SODIUM_CRYPTO_SECRETBOX_KEYBYTES);
// Do not reuse $nonce with the same key
$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
$ciphertext = sodium_crypto_secretbox('message to be encrypted', $nonce, $key);

// The same nonce and key are required to decrypt the $ciphertext
$plaintext = sodium_crypto_secretbox_open($ciphertext, $nonce, $key);
if ($plaintext !== false) {
    echo $plaintext . PHP_EOL;
}
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

message to be encrypted

Siehe auch

sodium_crypto_secretbox() - Authenticated shared-key encryption
sodium_crypto_secretbox_keygen() - Generate random key for sodium_crypto_secretbox
random_bytes() - Get cryptographically secure random bytes

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User Contributed Notes 1 note

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khalyomede at gmail dot com ¶

5 years ago


This method will return a string, or false if the data failed to be decrypted.

$key = 'secret';
$data = 'binarydata';
$nonce = random_bytes(SODIUM_CRYPT_SECRETBOX_NONCEBYTES);

$decrypted = sodium_crypto_secretbox_open($data, $nonce, $key);

if ($decrypted === false) {
  throw new Exception('failed to decrypt data');
}

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